Guide · Cold Plunge

Cold plunge running costs

Almost no chiller publishes a wattage, so this cannot be a lookup. Here is the arithmetic, the estimation method, and the variables that matter more than the chiller you bought.

By Sawyer V.Last updated September 7, 2026Published August 21, 2026

The equation

Same as every electricity calculation: kilowatts × hours running × your rate per kWh. The two hard parts are the kilowatts, which is not published, and the hours running, which depends on your setup rather than on the chiller.

Estimating the kilowatts

If your chiller publishes a wattage, use it. If it does not, the nameplate on the unit itself will — check the label before you plug it in, because that is a real figure rather than a marketing one.

Failing that, a clamp meter or a plug-in energy monitor gives you the actual draw, and a monitor that logs over a week gives you something far better: the real duty cycle. That is a $20 purchase that answers this question definitively for your setup, and we would do that rather than trust any published estimate — including ours.

Estimating the hours

This is where the real variation is, and it is a property of your tub and its siting, not of the chiller.

What drives duty cycle

Setup	Chiller behavior	Relative cost
Insulated tub, fitted lid, indoors, cool room	Cycles briefly and infrequently	Lowest
Insulated tub, lid, garage	Cycles more in summer	Low
Insulated tub, no lid, indoors	Cycles considerably more	Moderate
Uninsulated tub, no lid, outdoors, shaded	Runs a large fraction of the time	High
Uninsulated tub, no lid, direct sun	May struggle to hold at all	Highest, and may fail

The spread between the first and last rows is enormous — far larger than the difference between any two chillers. The lid is the single highest-leverage thing you can change, because the open water surface is the biggest heat path.

A worked example

Suppose you measure your chiller at 500 W and observe it running roughly 6 hours a day across a day of cycling. That is 3 kWh a day:

Daily and monthly cost at 500 W, 6 hours running

Rate per kWh	Per day	Per month (30 days)	Per year
$0.12	$0.36	$10.80	$131
$0.17	$0.51	$15.30	$186
$0.30	$0.90	$27.00	$328

Working: 0.5 kW × 6 h = 3 kWh/day. × rate = daily cost. Both inputs are illustrative — 500 W and 6 hours are placeholders, not measurements of any specific product. Substitute your own measured wattage and observed runtime, and your own rate from your utility bill.

The shape of the answer is what matters: for most home setups this is a monthly cost in the low tens of dollars rather than a hundreds-of-dollars problem. It is not free, and it is not the reason to avoid a chiller.

How this compares to ice

A meaningful comparison needs your ice price, which we do not have. What we can give you is the physical quantity: dropping a 100-gallon tub by 10 °F takes roughly 58 lb of ice as a theoretical floor, calculated from the latent heat of fusion. Multiply by your local price and your session frequency and set it against the electricity table above.

The full comparison, including the upfront cost and the non-financial variables, is in chiller vs ice.

How to cut the cost

1Fit a lid. By a distance the biggest lever. The open water surface is the main heat path and a fitted insulated lid closes most of it.
2Get it out of the sun. Direct sun on a tub is a substantial heat load that a chiller has to fight all afternoon.
3Insulate the tub, if it is not already. Even a wrap helps.
4Raise the target temperature. Holding 55 °F is meaningfully easier than holding 40 °F, and published protocols commonly sit between 50 and 59 °F — you may be paying for cold you do not need.
5Turn it off in winter, if you live somewhere cold. Below about 50 °F ambient, outside air does the job for nothing.
6Use less water. Fill to the depth you need rather than the brim.

What we are not telling you

A single number for what a cold plunge costs to run. We do not have one, and neither does anyone else who is being straight with you — the wattage is not published, and the duty cycle depends on your tub, your lid, your room and your climate.

What we can tell you is the equation, the variables in order of importance, and that a plug-in energy monitor answers it definitively for about the price of a bag of ice. That is a better answer than a confident average.

Questions people actually ask

How much does it cost to run a cold plunge chiller?

It cannot be answered precisely from published data, because no chiller listing we surveyed publishes a wattage. For most home setups the shape of the answer is a monthly cost in the low tens of dollars. To get your own number, read the wattage off the unit's nameplate and use a plug-in energy monitor to observe the real duty cycle.

Do cold plunge chillers run constantly?

No — they cycle. Once the tub is at temperature the chiller only runs enough to match heat leaking in. How often that is depends almost entirely on insulation, whether there is a lid, and where the tub lives. An uninsulated tub in direct sun is a very different proposition from an insulated tub with a lid indoors.

What is the cheapest way to run a cold plunge?

Fit an insulated lid — the open water surface is the biggest heat path and a lid closes most of it. Then keep the tub out of direct sun, insulate it, and raise the target temperature if you are chasing a coldness the research does not require. In a cold climate, switch the chiller off for the winter months.

Is a cold plunge cheaper to run than a sauna?

They are different shapes of cost rather than different amounts. A sauna draws a lot of power for a short session — a 6 kW heater for 45 minutes is about $0.77 at $0.17/kWh at the upper bound. A chiller draws less but runs intermittently around the clock. Both are modest; neither should decide whether you buy one.

Sources

US Energy Information Administration — average retail price of electricity by state — checked Sep 7, 2026
NIST Chemistry WebBook — properties of water and ice used in the comparison arithmetic — checked Sep 7, 2026

Every pick on this page comes from published specifications, not from hardware we own. Read how we pick — including what spec-led ranking cannot tell you.